Correct Answer: Obelia

Solution : The correct option is Obelia .

Obelia is a type of hydrozoan, and its life cycle involves alternating between a sexually reproducing medusa stage and an asexually reproducing polyp stage. Metagenesis is a phenomenon in the life cycle of certain organisms where they undergo the alternation of generations, meaning they switch between different forms or stages in their life cycle. It involves a sexual reproductive stage and an asexual reproductive stage.